As disclosed in unexamined Japanese Utility Model Publication No. S62-116740, a connecting structure for medical use that includes a male connector and a female connector for connecting medical components such as tubes are well known. The male connector includes a male luer portion having a tapered outer periphery. The female connector includes a female luer portion having a tapered inner periphery. The male connector and the female connector are threadedly engageable with each other. The male luer portion and the female luer portion can be joined together with a pressing force working therebetween by advancement of the threaded engagement between the male connector and the female connector. By this arrangement, desired sealing properties can be obtained.
When the connectors are not threadedly engaged tightly enough in the connecting structure mentioned above, sufficient sealing properties may not be obtained. Without sufficient sealing properties, the connectors may be disconnected when subjected to impact.
When the connectors are threadedly engaged too tightly, the male luer portion and the female luer portion may bite strongly into each other. In such a state, the threaded engagement between the connectors may not be able to be loosened. Accordingly, the connectors may not be able to be disconnected from each other nor connected to another connector. Excessive tightening torque may cause breakages such as cracking to the male luer portion and the female luer portion.
Granted Japanese Utility Model Publication No. 3108468 discloses a stopper provided in one of the male connector and the female connector. Depth of threaded engagement is controlled by the stopper in order to prevent excessive tightening.
However, according to the features disclosed in Japanese Utility Model Publication No. 3108468, manufacturing errors may cause an error in a relationship between the controlled depth of threaded engagement and a tightening torque for securing appropriate sealing properties. Sometimes, the error in the relationship may be so significant that the appropriate sealing properties and the prevention of excessive tightening cannot be realized at the same time.